Losartan potassium is a water soluble antihypertensive agent with short half-life. Controlling its release will improve patient compliance. The benefit will be extended for geriatric patients if the developed system was liquid. The objective of this work was to develop controlled release oral liquid losartan potassium. This employed a combination of in situ gelation and coating drug particles with pH-dependent polymer (Eudragit® L100). Solid dispersion (SD) prepared at 1:1, 1:1.5 and 1:2 drug:polymer rations, respectively. Sodium alginate solution was loaded with either pure drug or solid dispersion, in presence and absence of 1% w/v chitosan. These systems were evaluated for the drug release using continuous pH variation study. Alginate formulation with pure drug underwent in situ gelation in the gastric conditions but lost the gelling strength in the intestinal phase with burst drug release. Loading the formulation with SD resulted in controlled drug release both in the gastric and intestinal phases. Increasing eudragit concentration in SD decreased drug released with total release efficiency of 62.1, 53.0 and 41.7%. Incorporation of chitosan at reduced further drug release rate reaching 21% at the higher eudragit concentration. The study provided the formulator with a range of oral liquid formulations for controlled release of losartan potassium.
Key words: losartan potassium, in situ gelling, controlled release, Eudragit® L100, sodium alginate
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